Overall, client satisfaction with hearing-aid systems is very low. Today, only 2 percent of Americans wear a hearing aid, while it is believe that at least 10 percent of Americans could benefit from a hearing assistive device. Innovations at the microphone level have a direct positive impact on hearing aid performance. This work is focused on commercializing a new type of MEMS microphone that will set a new benchmark with respect to the combination of high fidelity and small size. A revolutionary approach is taken in which interference of light is used to detect sound. The system combines optical and mechanical elements fabricated on silicon with semiconductor lasers and optoelectronics to form a robust capsule consistent in size with the smallest microphones demonstrated to date, but with fidelity rivaled only by microphones 100x larger in size. With ultra-low noise microphones, hearing aid system developers will be able to integrate more advanced algorithms aimed at solving a long-standing problem for hearing aid users known as the "cocktail party" problem. Binaural signal processing is another hearing aid technology that will benefit from high fidelity microphone capsules with well matched dynamics. A microphone able to meet the demands of these applications is likely to have a broad impact on the hearing health community. PUBLIC HEALTH RELEVANCE: High performance micro machined microphones for hearing aids Relevance this innovation is in support of the NIDCD mission to support efforts to create and refine devices that may replace or substitute for lost and impaired sensory and communication functions. Despite the growing importance of hearing assistive devices to the public and user dissatisfaction with such devices, relatively few commercial innovations have resulted to address this challenge. This innovation seeks to make a substantial contribution in this area.